IUI Centro Iberoamericano de la Biodiversidad, Universidad de Alicante, San Vicente del Raspeig, Alicante, Spain.
PLoS One. 2013 Jul 16;8(7):e69277. doi: 10.1371/journal.pone.0069277. Print 2013.
Thorectes lusitanicus, a typically coprophagous species is also actively attracted to oak acorns, consuming, burying them, and conferring ecophysiological and reproductive advantages to both the beetle and the tree. In this study, we explored the possible relation between diet shift and the health status of T. lusitanicus using a generalist entomopathogenic fungus (Metarhizium anisopliae) as a natural pathogen. To measure the health condition and immune response of beetles, we analysed the protein content in the haemolymph, prophenoloxidase (proPO) content, phenoloxidase (PO) activity and mortality of beetles with diets based on either acorns or cow dung. Protein content, proPO levels and PO levels in the haemolymph of T. lusitanicus were found to be dependent on the type of diet. Furthermore, the beetles fed with acorns developed a more effective proPO-PO system than the beetles fed with cow dung. Furthermore, a significant decrease in mortality was observed when infected individuals were submitted to an acorn-based diet. In addition to enhancing an understanding of the relevance of dietary change to the evolutionary biology of dung beetles, these results provide a more general understanding of the ecophysiological implications of differential dietary selection in the context of fitness.
葡萄牙粪金龟是一种典型的食粪性物种，它也会被橡果积极吸引，食用、埋藏橡果，从而为甲虫和树木带来生态生理和繁殖上的优势。在这项研究中，我们使用一种广谱的昆虫病原真菌（绿僵菌）作为天然病原体，探讨了食性转变与葡萄牙粪金龟健康状况之间的可能关系。为了衡量甲虫的健康状况和免疫反应，我们分析了以橡果或牛粪为食的甲虫的血淋巴蛋白含量、酚氧化酶原（proPO）含量、酚氧化酶（PO）活性和死亡率。结果表明，葡萄牙粪金龟的血淋巴蛋白含量、proPO 水平和 PO 活性取决于其饮食类型。此外，以橡果为食的甲虫比以牛粪为食的甲虫发育出了更有效的 proPO-PO 系统。此外，当感染个体被喂食以橡果为基础的饮食时，死亡率显著下降。这些结果除了增强了对食性变化与蜣螂进化生物学相关性的理解外，还为在适应度背景下对不同饮食选择的生态生理意义提供了更广泛的认识。
